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LFXTAL066431 32.768 kHz Crystal Equivalent & Substitute Parts
Part Overview
The LFXTAL066431 is a 32.768 kHz tuning fork crystal manufactured by IQD Frequency Products, designed for real-time clock (RTC) and timing applications requiring fundamental mode operation. This component operates across the industrial temperature range of -40°C to 85°C with a frequency tolerance of ±20ppm and a load capacitance of 7pF. The part is ROHS3 compliant and currently active in production with 5,588 units in stock.
Equivalent and substitute parts are identified when component availability is limited, supply chain disruptions occur, or design flexibility is required for manufacturing optimization. Substitute crystals must maintain identical electrical performance characteristics including frequency, tolerance, ESR, load capacitance, and operating temperature range to ensure direct functional replacement without circuit redesign.
Substiute Parts
Key Parameters
| Parameter | Value | Unit | Substitution Criticality |
|---|---|---|---|
| Frequency | 32.768 | kHz | Critical - Must Match Exactly |
| Frequency Tolerance | ±20 | ppm | Critical - Must Match Exactly |
| Load Capacitance | 7 | pF | Critical - Affects Circuit Tuning |
| ESR (Equivalent Series Resistance) | 90 | kOhms | Critical - Affects Oscillator Startup |
| Operating Mode | Fundamental | - | Critical - Must Match Exactly |
| Operating Temperature Range | -40 to 85 | °C | Critical - Must Match or Exceed |
| Package Type | 2-SMD, No Lead | - | Critical - Physical Compatibility |
| Mounting Type | Surface Mount | - | Critical - Assembly Process |
| RoHS Status | ROHS3 Compliant | - | Required - Regulatory Compliance |
Substitute Part Grouping Explanation
Substitution logic for the LFXTAL066431 is based on strict electrical and mechanical parameter matching. The primary substitution criteria are:
Frequency and Tolerance: All substitute parts must operate at 32.768 kHz with ±20ppm tolerance. This parameter is non-negotiable as it determines timing accuracy in RTC applications.
Load Capacitance: The LFXTAL066431 specifies 7pF load capacitance. Substitute parts with different load capacitance values (5pF, 6pF, 9pF) require circuit board tuning capacitor adjustment and are classified as secondary substitutes. Parts with matching 7pF load capacitance are primary substitutes.
ESR (Equivalent Series Resistance): The specified ESR is 90 kOhms. Parts with different ESR values (60 kOhms) affect oscillator startup behavior and power consumption, requiring circuit validation.
Operating Temperature Range: All substitutes must support -40°C to 85°C operation to maintain specification compliance.
Package and Mounting: All parts use 2-SMD, No Lead surface mount packages with dimensions 0.063" L x 0.039" W (1.60mm x 1.00mm), except ECS-.327-7-1210-TR and ECS-.327-9-1210-TR which use 0.047" L x 0.039" W (1.20mm x 1.00mm) packages. Package dimension differences require PCB footprint verification.
Regulatory Compliance: All substitutes are ROHS3 compliant and REACH unaffected, maintaining regulatory alignment with the main part.
Parameter Comparison
| Manufacturer Part Number | Manufacturer | Frequency (kHz) | Tolerance (ppm) | Load Capacitance (pF) | ESR (kOhms) | Package Dimensions (mm) | Inventory (Pcs) | Substitution Class |
|---|---|---|---|---|---|---|---|---|
| LFXTAL066431 | IQD Frequency Products | 32.768 | ±20 | 7 | 90 | 1.60 x 1.00 | 5,588 | Main Part |
| LFXTAL066198 | IQD Frequency Products | 32.768 | ±20 | 9 | 90 | 1.60 x 1.00 | 14,151 | Secondary |
| ABS05-32.768KHZ-9-T | Abracon LLC | 32.768 | ±20 | 9 | 90 | 1.60 x 1.00 | 322,704 | Secondary |
| CM1610H32768DZBT | Citizen Finedevice Co Ltd | 32.768 | ±20 | 6 | 90 | 1.60 x 1.00 | 11,265 | Secondary |
| CM9V-T1A-32.768KHZ-9PF-20PPM-TA-QC | Micro Crystal AG | 32.768 | ±20 | 9 | 90 | 1.60 x 1.00 | 45,965 | Secondary |
| ECS-.327-5-16-TR | ECS Inc. | 32.768 | ±20 | 5 | 90 | 1.60 x 1.00 | 32,752 | Secondary |
| ECS-.327-6-16R-TR | ECS Inc. | 32.768 | ±20 | 6 | 60 | 1.60 x 1.00 | 62,929 | Secondary |
| ECS-.327-7-1210-TR | ECS Inc. | 32.768 | ±20 | 7 | 90 | 1.20 x 1.00 | 141,759 | Primary* |
| ECS-.327-9-1210-TR | ECS Inc. | 32.768 | ±20 | 9 | 90 | 1.20 x 1.00 | 36,193 | Secondary |
| ECS-.327-9-16-TR | ECS Inc. | 32.768 | ±20 | 9 | 90 | 1.60 x 1.00 | 177,410 | Secondary |
| SC12S-7PF20PPM | Seiko Instruments | 32.768 | ±20 | 7 | 90 | 1.27 x 1.05 | 16,731 | Primary* |
*Primary substitutes match load capacitance and ESR but require PCB footprint verification due to package dimension differences.
Engineering Selection Recommendations
Primary Substitutes (Electrical Match, Footprint Verification Required)
ECS-.327-7-1210-TR and SC12S-7PF20PPM are electrically equivalent to LFXTAL066431, matching the critical 7pF load capacitance and 90 kOhms ESR. Both parts are ROHS3 compliant and support the full -40°C to 85°C operating temperature range. However, package dimensions differ from the main part:
- ECS-.327-7-1210-TR: 1.20mm x 1.00mm (versus 1.60mm x 1.00mm main part)
- SC12S-7PF20PPM: 1.27mm x 1.05mm (versus 1.60mm x 1.00mm main part)
These parts require PCB footprint verification and may necessitate layout adjustments. ECS-.327-7-1210-TR offers significantly higher inventory (141,759 units) compared to the main part (5,588 units), providing superior supply chain availability.
Secondary Substitutes (Load Capacitance Variation)
Parts with 9pF, 6pF, or 5pF load capacitance (LFXTAL066198, ABS05-32.768KHZ-9-T, CM1610H32768DZBT, CM9V-T1A-32.768KHZ-9PF-20PPM-TA-QC, ECS-.327-5-16-TR, ECS-.327-9-1210-TR, ECS-.327-9-16-TR) require circuit board tuning capacitor adjustment to achieve proper oscillation frequency. These substitutes are suitable only when circuit design permits load capacitance modification and oscillator tuning validation is performed.
ESR Variation Consideration
ECS-.327-6-16R-TR specifies 60 kOhms ESR versus the 90 kOhms requirement. This lower ESR may reduce oscillator startup time and power consumption but requires oscillator circuit validation to confirm compatibility with the specified load capacitance and frequency stability.
Regulatory and Compliance Status
All identified substitutes maintain ROHS3 compliance and REACH unaffected status, ensuring regulatory alignment with the main part across all applicable jurisdictions.
Frequently Asked Questions (FAQ)
Q: Can I use a substitute crystal with different load capacitance (9pF instead of 7pF)?
A: Load capacitance differences require adjustment of the circuit board tuning capacitors connected to the crystal oscillator. The oscillator circuit must be retuned to achieve the specified 32.768 kHz frequency and ±20ppm tolerance. This substitution is permissible only when circuit design allows capacitor modification and oscillator performance is validated through testing.
Q: What is the impact of ESR differences on circuit performance?
A: ESR (Equivalent Series Resistance) affects oscillator startup behavior and power consumption. The specified 90 kOhms ESR is matched by most substitutes. ECS-.327-6-16R-TR with 60 kOhms ESR may reduce startup time and power draw but requires oscillator circuit validation to confirm stable operation at the specified frequency and tolerance.
Q: Are package dimension differences critical for substitution?
A: Yes. ECS-.327-7-1210-TR (1.20mm x 1.00mm) and SC12S-7PF20PPM (1.27mm x 1.05mm) have different footprints than the main part (1.60mm x 1.00mm). PCB layout verification is required to confirm that the smaller package dimensions are compatible with existing solder pads and assembly equipment. Footprint mismatch may require PCB redesign.
Q: Which substitute offers the best supply chain availability?
A: ECS-.327-9-16-TR provides the highest inventory at 177,410 units, followed by ECS-.327-7-1210-TR at 141,759 units. However, ECS-.327-9-16-TR requires load capacitance adjustment (9pF versus 7pF), while ECS-.327-7-1210-TR is electrically equivalent but requires footprint verification.
Q: Do all substitutes support the same operating temperature range?
A: Yes. All identified substitutes support the full -40°C to 85°C operating temperature range specified for the main part, ensuring thermal performance equivalence across industrial applications.
Q: Are all substitutes ROHS3 compliant?
A: Yes. All substitute parts listed are ROHS3 compliant and REACH unaffected, maintaining regulatory compliance with the main part for all applicable markets and applications.
Q: What is the difference between primary and secondary substitutes?
A: Primary substitutes (ECS-.327-7-1210-TR, SC12S-7PF20PPM) match the 7pF load capacitance and 90 kOhms ESR but require PCB footprint verification due to package dimension differences. Secondary substitutes have different load capacitance values and require circuit tuning capacitor adjustment and oscillator retuning to achieve specification compliance.
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